xnu-4903.270.47.tar.gz

[apple/xnu.git] / bsd / kern / kern_backtrace.c

diff --git a/bsd/kern/kern_backtrace.c b/bsd/kern/kern_backtrace.c
index 925994950dc6390348e9a4b960e57dcf40357c84..29329bf7797c60928c16cf7bc3878519b9ab935c 100644 (file)
--- a/bsd/kern/kern_backtrace.c
+++ b/bsd/kern/kern_backtrace.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2016, 2019 Apple Computer, Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  *
@@ -32,6 +32,8 @@
 #include <sys/sysctl.h>
 #include <sys/systm.h>
 
+#if DEVELOPMENT || DEBUG
+
 #define MAX_BACKTRACE  (128)
 
 #define BACKTRACE_USER (0)
@@ -39,21 +41,23 @@
 static int backtrace_sysctl SYSCTL_HANDLER_ARGS;
 
 SYSCTL_NODE(_kern, OID_AUTO, backtrace, CTLFLAG_RW | CTLFLAG_LOCKED, 0,
-       "backtrace");
+    "backtrace");
 
 SYSCTL_PROC(_kern_backtrace, OID_AUTO, user,
-       CTLFLAG_RW | CTLFLAG_LOCKED, (void *)BACKTRACE_USER,
-       sizeof(uint64_t), backtrace_sysctl, "O", "take user backtrace of current thread");
+    CTLFLAG_RW | CTLFLAG_LOCKED, (void *)BACKTRACE_USER,
+    sizeof(uint64_t), backtrace_sysctl, "O",
+    "take user backtrace of current thread");
 
 static int
 backtrace_sysctl SYSCTL_HANDLER_ARGS
 {
 #pragma unused(oidp, arg2)
-       uintptr_t *bt;
-       uint32_t bt_len, bt_filled;
        uintptr_t type = (uintptr_t)arg1;
-       bool user_64;
-       int err = 0;
+       uintptr_t *bt = NULL;
+       uint32_t bt_len = 0, bt_filled = 0;
+       size_t bt_size = 0;
+       int error = 0;
+       bool user_64 = false;
 
        if (type != BACKTRACE_USER) {
                return EINVAL;
@@ -64,23 +68,27 @@ backtrace_sysctl SYSCTL_HANDLER_ARGS
        }
 
        bt_len = req->oldlen > MAX_BACKTRACE ? MAX_BACKTRACE : req->oldlen;
-       bt = kalloc(sizeof(uintptr_t) * bt_len);
+       bt_size = sizeof(bt[0]) * bt_len;
+       bt = kalloc(bt_size);
        if (!bt) {
                return ENOBUFS;
        }
-       bzero(bt, sizeof(uintptr_t) * bt_len);
-       err = backtrace_user(bt, bt_len, &bt_filled, &user_64);
-       if (err) {
+       memset(bt, 0, bt_size);
+       error = backtrace_user(bt, bt_len, &bt_filled, &user_64);
+       if (error) {
                goto out;
        }
+       bt_filled = min(bt_filled, bt_len);
 
-       err = copyout(bt, req->oldptr, bt_filled * sizeof(uint64_t));
-       if (err) {
+       error = copyout(bt, req->oldptr, sizeof(bt[0]) * bt_filled);
+       if (error) {
                goto out;
        }
        req->oldidx = bt_filled;
 
 out:
-       kfree(bt, sizeof(uintptr_t) * bt_len);
-       return err;
+       kfree(bt, bt_size);
+       return error;
 }
+
+#endif /* DEVELOPMENT || DEBUG */